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C#
Q1. In which of these situations are interfaces better than abstract classes?
Q2. Which statement is true of delegates?
Official documentation: Delegates
Q3. Which choice best defines C#'s asynchronous programming model?
Official documentation: Task asynchronous programming model resposta correta --> var contacts
= new List();
Q4. How would you determine if a class has a particular attribute?
 When you need to define an object type's characteristics, use an interface. When you need to
define an object type's capabilities, use an abstract class.
 Interfaces are a legacy of older versions of C#, and are interchangeable with the newer abstract
class feature.
 When you need a list of capabilities and data that are classes-agnostic, use an interface. When
you need a certain object type to share characteristics, use an abstract class.
 You should use both an interface and an abstract class when defining any complex object.
 Delegates are not supported in the current version of C#
 They cannot be used as callbacks.
 Only variables can be passed to delegates as parameters.
 They can be chained together.
 reactive
 inherited callback
 task-based
 callback-based
 .
var type = typeof(SomeType); 
var attribute = type.GetCustomAttribute<SomeAttribute>();
 .
var typeof(MyPresentationModel).Should().BeDecoratedWith<SomeAttribute>();
 .
Attribute.GetCustomAttribute, typeof(SubControllerActionToViewDataAttribute)
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/delegates/#delegates-overview
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/async/task-asynchronous-programming-model
1. Official documentation: Attribute Class
2. Official documentation: Attribute.GetCustomAttribute Method
Q5. What is the difference between the ref and out keywords?
1. Official documentation: ref
2. Official documentation: out parameter modifier
Q6. How could you retrieve information about a class, as well as create an instance at runtime?
Official documentation: Reflection
Q7. What is this code an example of?
 .
Attribute.GetCustomAttribute(typeof(ExampleController), typeof(SubControllerActionToViewData
 Variables passed to out specify that the parameter is an output parameter, while ref specifies
that a variable may be passed to a function without being initialized.
 Variables passed to ref can be passed to a function without being initialized, while out specifies
that the value is a reference value that can be changed inside the calling method.
 Variables passed to out can be passed to a function without being initialized, while ref specifies
that the value is a reference value that can be changed inside the calling method.
 Variables passed to ref specify that the parameter is an output parameter, while out specifies
that a variable may be passed to a function without being initialized.
 reflection
 serialization
 abstraction
 dependency injection
 private static object objA; 
 private static object objB; 
 private static void performTaskA() 
 { 
 lock (objB) 
 { 
 Thread.Sleep(1000); 
 lock (objA) { } 
 } 
 } 
 private static void PerformTaskB() 
 { 
https://docs.microsoft.com/en-us/dotnet/api/system.attribute?view=net-5.0
https://docs.microsoft.com/en-us/dotnet/api/system.attribute.getcustomattribute?view=net-5.0
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/ref
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/out-parameter-modifier
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/reflection
Official documentation: Deadlocks and race conditions
Q8. What is the difference between an anonymous type and a regular data type?
Official documentation: Anonymous Types
Q9. When would you use a Dictionary rather that an Array type in your application?
Official documentation: Dictionary<TKey,TValue> Class
Q10. What is the difference between a.Equals(b) and a == b?
1. Official documentation: Object.Equals
2. c-sharpcorner: Equality Operator(==) vs .Equals()
Q11. Which choice best describes a deadlock situation?
 lock (objA) 
 { 
 lock (objB) { } 
 } 
 }
 a private class that uses multithreading
 multithread coding
 thread mismanagement
 a potential deadlock
 Anonymous types don't have type names
 Anonymous types can only be static
 Anonymous types can be used only in struts
 Anonymous types don't work with LINQ.
 when you need a jagged collection structure
 when you need to store values of the same type
 when you need to store key-value pairs rather than single values
 when you need an ordered, searchable list
 The .Equals method compares reference identities while the  ==  compares contents.
 The .Equals method compares primitive values while  ==  compares all values.
 The .Equals method compares contents while  ==  compares reference identity.
 The .Equals method compares reference type while  ==  compares primitive value types
 when you try to instantiate two objects at the same time in the same class or struct
 when you are trying to execute an action after a user event is registered
 when simultaneous instructions are waiting on each other to finish before executing
 when you try to execute a series of events simultaneously on multiple threads
https://docs.microsoft.com/en-us/dotnet/standard/threading/managed-threading-best-practices#deadlocks-and-race-conditions
https://docs.microsoft.com/en-us/dotnet/csharp/fundamentals/types/anonymous-types
https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.dictionary-2?view=net-5.0
https://docs.microsoft.com/en-us/dotnet/api/system.object.equals
https://www.c-sharpcorner.com/UploadFile/3d39b4/difference-between-operator-and-equals-method-in-C-Sharp
Official documentation: Deadlocks and race conditions
Q12. How does the async keyword work?
Official documentation: async
Q13. What is an object in C#?
Official documentation: Objects
Q14. Which code snippet declares an anonymous type named userData?
Official documentation: Anonymous Types
Q15. What will be returned when this method is executed?
public void userInput(string charParameters) { }
Official documentation: void
Q16. In what order would the employee names in this example be printed to the console?
 It allows access to asynchronous methods in the C# API
 It allows thread pooling and synchronous processes in static classes.
 It allows the await keyword to be used in a method
 It allows access to synchronous methods in the C# API
 a class or struct, including its variables and functions
 a primitive data type that can be created only at compile time
 a value type that can be used only with an abstract class
 an instance of a class or struct that includes fields, properties, and/or methods
  var<<!---->T> userData = new <<!---->T> { name = "John", age = 32 };
  var userData = new { name = "John", age = 32 };
  AType userData = new AType { name = "John", age = 32 };
  Anonymous<T> userData = new Anonymous<T> { name = "John", age = 32 };
 nothing
 a Boolean
 a string variable
 an integer
string[] employees = { "Joe", "Bob", "Carol", "Alice", "Will" }; 
IEnumerable<string> employeeQuery = from person in employees 
 orderby person 
 select person; 
https://docs.microsoft.com/en-us/dotnet/standard/threading/managed-threading-best-practices#deadlocks-and-race-conditions
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/async
https://docs.microsoft.com/en-us/dotnet/csharp/fundamentals/object-oriented/objects
https://docs.microsoft.com/en-us/dotnet/csharp/fundamentals/types/anonymous-types
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/void
dotnetpattern: LINQ OrderBy Operator
Q17. Lambda expressions are often used in tandem with which of the following?
Official documentation: Language Integrated Query (LINQ) OverviewQ18. What is the correct formatting for single line and multiline comments?
w3schools: C# Comments
Q19. How do you make a method in an abstract class overridable?
1. Official documentation: virtual
2. Official documentation: abstract
Q20. How would you write code for an integer property called Age with a getter and setter?
foreach(string employee in employeeQuery) 
{ 
 Console.WriteLine(employee); 
}
 ascending
 unordered
 descending
 first in, first out
 Namespaces
 LINQ
 Type Aliasing
 Assemblies
  /_/ - Single Line   /_ - Multiline
  // Multiline   /_ Single Line _/
  //\* Multiline   / Single Line
  // Single Line   /* Multiline */
 Make it public
 Make it static
 Make it private
 Make it virtual
 public int Age { get - set }
 public int Age: get set;
 public int Age (get, set );
 public int Age { get; set; }
http://dotnetpattern.com/linq-orderby-operator
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/linq/
https://www.w3schools.com/cs/cs_comments.php
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/virtual
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/abstract
Official documentation: Using Properties
Q21. What is an abstract class?
Official documentation: Abstract and Sealed Classes and Class Members
Q22. When using a thread pool what happens to a given thread after it finishes its task?
Official documentation: Thread pool characteristics
Q23. Which choice represents a class that inherits behavior from a base class?
Official documentation: Inheritance
Q24. What does operator overloading allow you to do?
Official documentation: Operator overloading
Q25. What is the main purpose of LINQ?
Official documentation: Language Integrated Query (LINQ) Overview
 a class that is denoted by the class keyword (can be seen and used by any other class in the
system--thus it is by default public)
 something denoted by the abstract keyword and used system wide; if you want any program
to create an object of a class you use the abstract class
 a class that is denoted by the virtual keyword
 a class that can be used only as base class
 The thread is destroyed and memory is freed up.
 The thread runs in loop until the next assignment.
 The thread goes inactive in the background and waits for garbage collection.
 The thread returns to the pool for reuse.
 a second base class
 a revised class
 a derived class
 a parent class
 hide built-in operators when necessary
 add methods to be interpreted by the compiler at runtime
 define how enums and other primitive value types work within the rest of the application
 define custom functionality for common operators like addition and equality
 to delete duplicate data
 to bind namespaces and assemblies
 to query and transform data
 to connect assemblies
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/using-properties
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/abstract-and-sealed-classes-and-class-members
https://docs.microsoft.com/en-us/dotnet/standard/threading/the-managed-thread-pool#thread-pool-characteristics
https://docs.microsoft.com/en-us/dotnet/csharp/fundamentals/object-oriented/inheritance
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/operators/operator-overloading
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/linq/#query-expression-overview
Q26. What is the correct syntax for a new generic list of strings named contacts?
Official documentation: List Class
Q27. What is the difference between throw exceptions and throw clauses?
1. Official documentation: throw
2. c-sharpcorner: Difference Between Throw Exception and Throw Clause
Q28. When an asynchronous method is executed, the code runs but nothing happens other than
a compiler warning. What is most likely causing the method to not return anything?
Official documentation: Starting tasks concurrently
Q29. What are C# events?
Official documentation: Introduction to events
Q30. What kind of values can arrays store?
Official documentation: Arrays
 public List contacts = new List();
 public List(string names) contacts = new List(string names)();
 var contacts = new List();
 var contacts = new List(string);
 Throw clauses fire only at runtime, while throw exceptions can fire at any time.
 Throw exceptions overwrite the stack trace, while throw clauses retain the stack information.
 Throw clauses overwrite the stack trace, while throw exceptions retain the stack information.
 Throw exceptions fire only at runtime, while throw clauses can fire during compile time.
 The return yield statement is missing at the end of the method.
 The method is missing an await keyword in its body.
 The wait keyword is missing from the end of the method.
 The yield keyword is missing from the method.
 system actions that communicate directly with the compiler at runtime
 actions that execute when the code compiles, generating logs and test output
 actions that generate notifications, which are sent to their registered listeners
 user-only methods that send data to the application's back end
 unordered collections of numeric values
 key-value pairs of any C# supported type
 class and struct instances
 multiple variables, or collections, of the same type
https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.list-1?view=net-5.0
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/throw
https://www.c-sharpcorner.com/UploadFile/akkiraju/difference-between-throw-exception-and-throw-clause/
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/async/#start-tasks-concurrently
https://docs.microsoft.com/en-us/dotnet/csharp/events-overview
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/arrays/
Q31. Given this enumeration, how would you access the integer-type value of
'AppState.Loading'?
enum AppState { OffLine, Loading, Ready }
Official documentation: Enumeration types
Q32. What character would you use to start a regular expression pattern at a word boundary?
1. regular-expressions: Word Boundaries
2. Official documentation: Regular Expression Language - Quick Reference
Q33. To conform to the following interface, which of its members need to be implemented?
Official documentation: interface
Q34. You're dealing with multiple assemblies in your program, but are worried about memory
allocation. At what point in the program life cycle are assemblies loaded into memory?
1. Official documentation: Assembly Loading
2. Stackoverflow : When exactly are assemblies loaded?
 string currentState = (string)AppState.Loading;
 string currentState = AppState.Loading.integralVal;
 int currentState = AppState.Loading.rawValue;
 int currentState = (int)AppState.Loading;
 d
 \a
 \b
 \w
public interface INameable 
{ 
 string FirstName { get; set; } 
 string LastName { get; } 
}
 Both the FirstName and LastName properties need to be implemented.
 Neither, they are both optional.
 Only the LastName property needs to be implemented.
 Only the FirstName property needs to be implemented.
 at runtime
 at compile time
 only when required
 only when programmatically loaded
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/enum#conversions
https://www.regular-expressions.info/wordboundaries.html
https://docs.microsoft.com/en-us/dotnet/standard/base-types/regular-expression-language-quick-reference
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/interface
https://docs.microsoft.com/en-us/dotnet/framework/deployment/best-practices-for-assembly-loading
https://stackoverflow.com/questions/21914692/when-exactly-are-assemblies-loaded
Q35. What is most accurate description of a regular expression?
1. Official documentation: Regular Expression Language - Quick Reference
2. Official documentation: .NET regular expressions
Q36. Why would you use a class field in C#
Officialdocumentation: Introduction to classes
Q37. When would you use generics in your code?
Official documentation: Generic classes and methods
Q38. What prints to the console when this code is executed?
1. Official documentation: Introduction to Delegates
 A regular expression is a C# tool used to parse HTML
 A regular expression is a special text string for describing a search patters.
 A regular expression allows a variable to be passed by reference.
 A regular expression allows a class to conform to the Equatable protocol.
 To define behaviours of the class
 To hold information and data contained in the class object
 To communicate between classes and object
 To store the class definition value
 to increase code performance
 all of these answers
 when code reuse is a priority
 when type safety is important
public delegate void AuthCallback(bool validUser); 
public static AuthCallback loginCallback = Login; 
public static void Login() 
{ 
 Console.WriteLine("Valid user!"); 
} 
public static void Main(string[] args) 
{ 
 loginCallback(true); 
}
 Login successful...
 Valid user!
 an error, because the method signature of Login doesn't match the delegate
 Login successful... Valid user!
https://docs.microsoft.com/en-us/dotnet/standard/base-types/regular-expression-language-quick-reference
https://docs.microsoft.com/en-us/dotnet/standard/base-types/regular-expressions
https://docs.microsoft.com/en-us/dotnet/csharp/fundamentals/types/classes
https://docs.microsoft.com/en-us/dotnet/csharp/fundamentals/types/generics
https://docs.microsoft.com/en-us/dotnet/csharp/delegates-overview
2. Official documentation: Introduction to Events
Q39. How would you declare a sealed class named User?
Official documentation: Abstract and Sealed Classes and Class Members
Q40. What is the difference between non-static and static classes?
1. stackoverflow
2. Official documentation: Static Constructors
Q41. Which characteristic prevents this code from compiling?
public int age="28"
c-sharpcorner: Type Safety in .NET
Q42. How would you serialize this class?
public class User {}
Official documentation: SerializableAttribute Class
Q43. How would you write a delegate named ResultCallback with an int parameter named
responseCode?
 public class User {}
 abstract User {}
 sealed class User {}
 private sealed class User {}
 non-static classes need to be initialized before use, while static classes do not
 non-static classes are accessible only from an interface while static classes are accessible from
anywhere
 non-static classes need to initialize all class members at runtime, while static classes do not
 non-static classes do not need to be initialized while static classes do
 type safety
 single inheritance
 dependency injection
 multiple inheritance
 Mark the User class with the  DeserializableAttribute .
 Declare the class as  public serializable class User {} .
 Mark the User class with the  SerializableAttribute  attribute.
 Declare the class as  private serializable class User {} .
 public delegate ResultCallback(int responseCode);
 public delegate void ResultCallback<(int) responseCode>;
https://docs.microsoft.com/en-us/dotnet/csharp/events-overview
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/abstract-and-sealed-classes-and-class-members
https://stackoverflow.com/questions/20451554/whats-the-function-of-a-static-constructor-in-a-non-static-class
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/static-constructors
https://www.c-sharpcorner.com/UploadFile/vikie4u/type-safety-in-net/
https://docs.microsoft.com/en-us/dotnet/api/system.serializableattribute?view=net-5.0
Official documentation: Delegates
Q44. What is the difference between a static and non-static method?
Official documentation: Static Members
Q45. What is the correct way to write an event named apiResult based on a delegate named
ResultCallback?
Official documentation: Introduction to events
Q46. When will the code inside finally block be executed in a try-catch statement?
Official documentation: try-catch
Q47. What method correctly extends the string class?
Q48. How are C# classes limited?
Official documentation: Class inheritance
 public void delegate ResultCallback<int responseCode>;
 public delegate void ResultCallback(int responseCode);
 non-static methods always need to have a void return type
 non-static methods do not have access to static member variables
 static methods do not have to instantiate an instance of the class to call the method
 static methods always have to be public
 public void event ResultCallback apiResult;
 public event ResultCallback(() -> apiResult);
 public event void ResultCallback
 public event ResultCallback apiResult;
 if there is an error, it won't execute at all
 between the try and catch blocks
 after the try and catch blocks
 when the finally block overrides the catch block and executes in its place
 public static string IsvalidName(this string i, string value) {}
 public static void IsvalidName(this string i, string value) {}
 public string IsvalidName(this string i, string value) {}
 public void IsvalidName(this string i, string value) {}
 They do not support multiple inheritance.
 They support multiple inheritance.
 They can have only a set number of properties.
 They can have only a set number of methods.
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/delegates/
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/static-classes-and-static-class-members#static-members
https://docs.microsoft.com/en-us/dotnet/csharp/events-overview
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/try-catch
https://docs.microsoft.com/en-us/dotnet/csharp/fundamentals/types/classes#class-inheritance
Q49. What function do namespaces perform?
Official documentation: namespace
Q50. What is the correct way to write a public property with a private backing field?
Official documentation: Using Properties
Q51. What is a thread pool?
 Namespaces calculate code coverage at runtime.
 Namespaces compile application code together at compile time.
 Namespaces group code together into a single repository.
 Namespaces separate code into groupings, control access, and void naming collisions.
 A
private int _password; 
pubic int Password = { get; set; }
 B
private int _password; 
public int Password = _password;
 C
private int _password; 
public int Password 
{ 
 get -> _password;
 set-> _password = value; 
}
 D
private int _password; 
public int Password 
{ 
 get { return _password; } 
 set { _password = value; } 
}
 a collection of synchronous methods created during initialization that cannot be reused
 a collection of threads created during initialization that can be reused
 a collection of threads only recognized at compile time that can be reused
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/namespace
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/classes-and-structs/using-properties
Official documentation: ThreadPool Class
Q52. When an object in C# is serialized, what is it converted to?
Official documentation: Serialization
Q53. What is a delegate
Official documentation: Delegates
Q54. What are the four keywords associated with exception handling in C#?
Tutorial Point
Q55. What is the main difference between the is and as operators?
Pluralsight guide
Q56. What is the difference between finally and finalize blocks?
 a collection of asynchronous methods created at compile time that cannot be reused
 XML
 JSON
 byte stream
 value stream
 a variable that holds a reference to a value type and its content
 a specific value type that can be used only in callback methods
 a type that holds a reference to a method with a particular parameter list and return type
 a custom variable type that can be used in abstract classes
 try, catch, valid, invalid
 try, valid, finally, throwtry, catch, finally, throw
 finally, throw, valid, invalid
 The is operator checks instance types, while the as operator checks the inherited type.
 The is operator checks primitive data types, while the as operator checks the object type.
 The as operator checks object type, while the is operator attempts to cast an object to a
specific type.
 The is operator checks object type, while the as operator attempts to cast an object to a
specific type.
 The finally block is called during the execution of a try and catch block, while the finalize
method is called after garbage collection.
 The finally block is called after the execution of a try and catch block, while the finalize method
is called just before garbage collection.
https://docs.microsoft.com/en-us/dotnet/api/system.threading.threadpool?view=net-5.0
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/serialization/
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/delegates/
https://www.tutorialspoint.com/csharp/csharp_exception_handling.htm#:~:text=Exceptions%20provide%20a%20way%20to,catch%2C%20finally%2C%20and%20throw.
https://www.pluralsight.com/guides/csharp-is-as-operators-is-expressions
C-sharpcorner
Q57. Your application has a value type called username that needs to be able to accept null
values, but this is generating compile-time errors. How would you fix this in code?
Q58. Which code snippet correctly declares a custom exception named InvalidResponse?
Official documentation: Exceptions
Q59. How would you write an enum variable called AppState with values for Offline, Loading,
and Ready?
Official documentation: Enum
Q60. What is the main difference between a value type and a reference type?
1. Official documentation: Value types
2. Official documentation: Reference types
Q61. What is the difference between the  break  and  continue  keywords?
 The finalize block is called before the execution of a try and catch block, while the finally
method is called just before garbage collection.
 The finalize block is called during the execution of a try and catch block, while the finally
method is called after garbage collection.
 Null username = null;
 string? username = null;
 Type? username = null;
 Optional username = null;
 struct InvalidResponse: Exception {}
 class InvalidResponse: Exception {}
 public Exception InvalidResponse = new Exception ();
 public Exception InvalidResponse () -> Exception;
 enum AppState = [Offline, Loading, Ready]
 enum AppState {"Offline", "Loading", "Ready"}
 enum AppState = {Offline, Loading, Ready}
 enum AppState {Offline, Loading, Ready}
 A value type can be any primitive type, while reference types must be type-agnostic.
 A value type refers to another value, while a reference type refers to a value in memory.
 A value type stores an actual value, while a reference type is a pointer to a value.
 A value type is available only at runtime, while a reference type is available only at compile
time.
https://www.c-sharpcorner.com/forums/final-finally-and-finalize
https://docs.microsoft.com/en-us/dotnet/standard/exceptions/how-to-create-user-defined-exceptions
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/enum
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/value-types
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/reference-types
Official documentation: Jump statements
Q62. Which code snippet correctly declares a variable named userId with a public  get  and
private  set ?
Official documentation: Properties
Q63. What is true about virtual methods?
1. Official documentation: virtual
2. c-sharpcorner: Virtual Method in C#
Q64. What is likely to happen if you have multiple threads accessing the same resource in your
program?
Official documentation: race conditions
Q65. How do you indicate that a string might be null?
 The  break  keyword is used to break out of multiple iteration statements, while  continue  can
only break out of code blocks that have single iterations.
 The  break  keyword literally breaks out of a control flow statement, while  continue  ignores
the rest of the control statement or iteration and starts the next one.
 The  break  keyword literally breaks out of the current control flow code and stops it dead,
while  continue  keeps executing the code after an exception is thrown.
 The  break  keyword jumps out of an iteration and then proceeds with the rest of the control
flow code, while  continue  stops the executing code dead.
  public int userID <get, set>;
  public int userID [get, private set];
  public int userID { get; private set; }
  public int userID = { public get, private set };
  Overriding virtual methods in a derived class is mandatory.
  Overriding virtual methods in a derived class is not possible.
  Virtual methods always need a default implementation.
  Virtual methods cannot have default implementation.
  resource overload
  thread jumping
  deadlock and race conditions
  nothing, since this is what threading is for
  A string cannot be nullable.
  string? myVariable
  string myVariable = null
  string(null) myVariable
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/statements/jump-statements
https://docs.microsoft.com/en-us/dotnet/csharp/properties
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/virtual
https://www.c-sharpcorner.com/UploadFile/3d39b4/virtual-method-in-C-Sharp/
https://docs.microsoft.com/en-us/archive/msdn-magazine/2008/october/concurrency-hazards-solving-problems-in-your-multithreaded-code
Official documentation: nullable value types
Q66. Do you need to declare an out variable before you use it?
Q67. How would you access the last two people in an array named People?
Explain: You can do this in C#. However, none of the above answers are correct. You could access
the last two items by using  People[^2..] . Please see issue #3354 for more information. See
also: Official Documentation: Ranges
Q68. When can anonymous types be created?
C-sharpcorner: Anonymous Types
Q69. What is true about thread multitasking?
Official Documentation: Threads
Q70. What accessibility level does this class field have ?
private string LastName;
Official Documentation: Accessibility Levels
  No, you can declare an out in the parameter list.
  Out variables are no longer part of C#.
  You must declare it if it is a primitive type.
  Yes.
  People[..^2]
  You cannot do this in C#.
  People[..^3]
  People[^2]
  at compile time
  after runtime
  at runtime
  after compile time
  Thread multitasking allows code to be executed concurrently
  Thread multitasking allows code to be executed only when handling a user event.
  Thread multitasking blocks code from being executed simultaneously to guard memory.
  Thread multitasking adds single-threaded code blocks together.
 It can be used by other code only in the same class or struct.
 It can be used by other code in a referenced assembly.
 It can be used only by code contained in a derived class.
 It can be used by other code in the same assembly.
https://learn.microsoft.com/en-us/dotnet/csharp/language-reference/builtin-types/nullable-value-types#declaration-and-assignment
https://github.com/Ebazhanov/linkedin-skill-assessments-quizzes/issues/3354
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/proposals/csharp-8.0/ranges
https://www.c-sharpcorner.com/UploadFile/ff2f08/anonymous-types-in-C-Sharp/
https://docs.microsoft.com/en-us/dotnet/standard/threading/threads-and-threading
https://docs.microsoft.com/en-us/dotnet/csharp/language-reference/keywords/accessibility-levels
Q71. How would you correctly declare a jagged array called 'partyInvites' with 10 empty
elements?
Official Documentation: Jagged Arrays
Q72. How could you pause a thread for three seconds?
Reference
Q73. What is wrong with this code?
Reference
Q74. Which statement is True?
  string[] partyInvites = new string[10];string[][] partyInvites = new string[10][];
  string[][] partyInvites = new string[10]();
  string <[]> partyInvites = new string <[10]>;
 Thread.Pause(3000);
 Thread.Resume(-3000);
 Thread.Suspend(3000);
 Thread.Sleep(3000);
void MyFunction() 
{ 
 { 
 int a = 10;
 int b = 20;
 int c = a + b; 
 } 
 Console.WriteLine(c); 
}
 Variable c is never used; displaying it on the console does not count as usage.
 Variables a and b are never used.
 You cannot place code inside brackets inside another block.
 Variable c no longer exists outside the block.
 All are true.
 None are true.
 string is a value type.
 string is an alias for String
https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/arrays/jagged-arrays
https://docs.microsoft.com/en-us/dotnet/api/system.threading.thread.sleep?view=net-6.0
https://stackoverflow.com/a/6136865